Abstract: The traditional method was used to determine the boiler make-up water treatment system of thermal power plant with large calculation and low efficiency. This paper proposed the establishment of equipment and its attribute database. And according to the water quality of the water source and the requirements of the unit for water quality indicators, the stable boiler make-up water treatment system equipment parameters were determined. This paper introduced the principle of system construction and the implementation process. In addition, through the design of a chemical water capacity increasing project in a thermal power plant, it was verified that the boiler make-up water treatment system determined by the database construction method had advantages over the traditional methods in terms of advancement, economy and flexibility.